Need help with 4x4 engaging problem

[FreedomRun]

I have a 1991 Explorer 4 door XLT. It has the push button 4x4 system. I had the transfer case motor replaced last winter because it died. I also had manual hubs installed. Now, I'm having problems with the automatic engagement system.

I push the 4x4 button up on the dash and can hear the click back at the module on every single push, but it can take up to 50-60 pushes for the 4x4 to engage. Then, if I push the button again to disengage it might take 6 pushes to re-engage the next time, then maybe 25 the next time, and so on.

What is the issue here? Is it a bad module? What can I do, or what would I tell my mechanic to test or check out?

I'm very disappointed with this automatic 4x4 system overall. It's just too darn complicated for what it's supposed to do. Is there any type of modification for drilling through the floorboards and attaching a metal rod to the transfer case for a manual engagement? Or maybe that's just wishful thinking.

I need my 4x4 system to be reliable and engage everytime I need it to engage, as my livelihood depends on it. So therefore, I am very grateful for you sharing your knowledge, expertise, and advice with me. Thank You.

 

[maroon93limited]

Bad shift motor, almost guarantee it. I'm going through the same problem right now. You can check out the repair info here. http://explorerforum.com/forums/showthread.php?t=202166

Or, in the odd case that it's un-repairable you can get a replacement from Dorman (any auto parts store should be able to get it), part number 600-800. I was able to find one for well under 200 bucks, brand spankin' new.

 

[CraigRK]

I had exactly the same issue (common), worsening until no 4x4. All I had to do was take off all the electrical connectors to the shift motor, clean them and put them back on. Works great now. You might get lucky by just doing this.

CraigK

 

[DeRocha]

I have a 1991 Explorer 4 door XLT. It has the push button 4x4 system. I had the transfer case motor replaced last winter because it died. I also had manual hubs installed. Now, I'm having problems with the automatic engagement system.

I push the 4x4 button up on the dash and can hear the click back at the module on every single push, but it can take up to 50-60 pushes for the 4x4 to engage. Then, if I push the button again to disengage it might take 6 pushes to re-engage the next time, then maybe 25 the next time, and so on.

What is the issue here? Is it a bad module? What can I do, or what would I tell my mechanic to test or check out?

I'm very disappointed with this automatic 4x4 system overall. It's just too darn complicated for what it's supposed to do. Is there any type of modification for drilling through the floorboards and attaching a metal rod to the transfer case for a manual engagement? Or maybe that's just wishful thinking.

I need my 4x4 system to be reliable and engage everytime I need it to engage, as my livelihood depends on it. So therefore, I am very grateful for you sharing your knowledge, expertise, and advice with me. Thank You.

The most common problem is a broken Stop Bumper within the Shift Motor. The worm drive on the electric shift motor puts out a LOT of Torq. As such when returning to the 2H position the shift motor doesn't stop on a dime and needs the Stop Bushing to Prevent:

• The Geared Position Sensor from traveling outside of it's operational range. When this occurs the 4x4 module becomes lost, and will no longer shift the T-Case as it cannot determine the position of the T-case selector shaft.
• The Geared Position Sensor from getting JAMMED against the metal stop. Once it gets jammed against the 2H Metal stop the shift motor may not have the power to Un-Jam itself when you push 4x4. This is why you are pushing 4x4 many times as the motor strains to un-jam itself. Eventually it does, but without a stop bumper the issues will keep occurring.

See the Shift Motor rebuild thread on how to fix the Shift Motor.

 

[FreedomRun]

Thanks for the assistance. I just said to hell with it and put on a Shiftster. Works for me.

 

[joppe]

4x4 failure

I recently bought a 1991 Explorer xlt, all original. when i push the 4x4 button nothing happens, no clicking sound can be Heard. i checked the Three relays under the Engine room fuse box and they are okay. the low speed button is not working either. should be a relay for this right? is it positioned somewhere else than under the hood? is it common that the push button fails? It seems to be a common problem with the Electric shifting motor, but then one should be able to hear a relay click or similiar. I have the chiltons manual, but it is not helping much in this case. thankful for a hint.

 

[murkinstock]

[MENTION=258495]joppe[/MENTION] The relays for the 4x4 are behind the left rear interior panel inside the module, so looking for them up there isn't going to lead you anywhere. lol Sorry.
Try this: 4x4 Troubleshooting guide

Also make sure you check fuse 17 under the dash

 

[RangerX]

joppe, this thread might help: 4x4 Troubleshooting guide

 

[joppe]

hi,thanks for your help. i replaced both the switches in the dashboard, and the computer in the back of the car. still no reaction. i meassured the Micro relays on the old computer box, and they were clicking when activated, but installed, nothing is Heard when pushing the 4x4 button. I can imaging a broken wire maybe. unfortunately my chilton manual is not including the blue print for 4 wd, it should be possible to meassure the push button's signal. any further suggestions?

 

[Gadget X]

Try unplugging the connector on the shift motor and cleaning the contacts, then use dielectric "bulb grease" when plugging it back in. If that doesn't help, you may need a new shift motor. Good luck with it!

 

[DeRocha]

@Joppe how did the 4x4 computer test out with the LEDs? I have worked on so many shift motors that I've lost count. 99% of the time the issue was the broken stop bumper, only one broken 4x4 module, one geared sensor detached from it's sensor board, followed by one broken dash switch.. The bad dash switch was due to a previous owner trying to mash the switch through the dash board in hopes to engage 4x4 (while the actual problem was the broken stop bumper)..

Moral of the story.. Every time I encounter an electronic 4x4 not working issue I imminently remove the old shift motor and inspect the geared sensor for any issues. Sometimes just removing the shift motor frees it up from years of NON use and it magically works again..

 

[Gadget X]

/\ /\ /\What he said! /\ /\ /\

 

[joppe]

yes, you got a very good Point. the main reason for me looking elsewhere is that I cannot hear the clicking of the inbuild relays (at the module). i had a friend pushing while holding the module, no sound or alike. there is no indication of the led when i push the button, and the 4x4 is not litten up on the dash either. i wonder, is the led near the push buttons only lit if the engaging is succesful?

 

[joppe]

hi again. after two weeks at work i continued working on the car. i removed the Electric motor, and if i connect 12 v dc to the two wires the motor works, shifting polarity it turns back. i put the car on stands and turned the shaft with a plier, and the gearbox shifts. no indication in the dash, not 4x4 high neither low. there is one wire going to a inductive switch (i Think) and one fixed (the one that sits center in the connector. could it still be something wrong inside the gear box? any suggestion where to look next?

 

[DeRocha]

Did you remove the shift motor cover? If so what did the stop bumper look like? Manually shifting an auto T-case into 4x4 will not cause any 4x4 lights to come on (but you're 100% in 4x4). The lights come on when the geared sensor selector inside the shift motor is rotated to the correct position.

 

[joppe]

No, I did not yet remove the cover, but I will now, thanks!!

 

[joppe]

the stop bumper looked ike new, unfortunately. I assembling it back together now.

 

[murkinstock]

Make sure you have a constant 12v on the darkgreen/lightgreen wire and 12v at the white/purple wire when the vehicle is on (these wires are at the shift module)

My problem was the wire had corroded under the trim by the drivers side door and I wasn't getting the constant power. Maybe you have a similar issue?

This might help explain what I'm talking about:

Maybe these will help:

 

[joppe]

hey, That was it!! Found a damaged wire where the set of wires coming through the floor. Repaired it, and now Everything is working Clockwork. thanks a lot, these drawings were really helpful, as well as all the hints were to look. I am most grateful!! thanks!

 

[murkinstock]

Awesome, I'm glad to hear! You're welcome! And give credit to BKennedy, and FR-425! They are the ones that helped me get mine going, making me able to help you!